Seeking assistance regarding Private Messages

Alright, I feel like an absolute fool again, and likely am. (I’m getting on in years):lol: My inbox is overflowing! Turns out there’s a limit of just 50 messages stored at once. (Who would have guessed?) I notice small checkboxes on the right side that let me select items, but I haven’t discovered how to actually remove them yet. If anyone else has cracked the code for deleting messages, please lend a hand!